KIN 4310 1nd Edition Lecture 8 Outline of Last Lecture I Terms True Score II Terms Observed Score III Terms Error IV Levels of Measurement V Nominal Scales VI Ordinal Scales VII Interval Scales VIII Ratio Scales IX Levels of Measurement X Objectives Reliability XI Reliability XII Reliability XIII Reliability XIV Reliability XV Test Retest Reliability XVI Interrater Reliability XVII Internal Consistency Reliability XVIII Parallel Forms Consistency These notes represent a detailed interpretation of the professor s lecture GradeBuddy is best used as a supplement to your own notes not as a substitute XIX What is Reliable XX Reliability Example XXI Reliability Example cont XXII Improving Reliability Outline of Current Lecture I Review Questions Current Lecture I Review Questions a Which of the following is an example of quantitative data i Diastolic blood pressure in mmHg b What is a hypothesis i An educated guess based on an observation it is the lowest level of scientific knowledge c What is statistics i A mathematical discipline for gathering illustrating making scientific conclusions from data d What is a population A census A sample i A population is a collection of all things to which the hypothesis refers to ii A census is an attempt to measure everyone in the population iii A sample is an attempt to measure a subset of a population e Describe 3 different types of sampling i Random ii Cluster iii Convenience iv Stratified v Systematic f A graduate student randomly selects 48 middle schools and interviews all of the math teachers at each school to gather data on new curriculum What type of sampling is being used for this study i Cluster g Why is random sampling good i It eliminates bias but it is hard to implement h What are descriptive statistics i A set of tools used to describe characteristics of samples ii Everything we have discussed so far i What is a correlational study i Observational study looks for relationships of two variables j k l m n o p q r s t u v w x ii Going to measure subject two times and will have paired data What is an experimental study i Manipulative one variable is controlled by experimenter it can show causation A study found a positive correlation between number of cell phone subscriptions and brain tumors in nineteen US states r 0 950 i This study was observational Name 3 measures of central tendency i Mean median and mode Name 3 measures of variability i Range s d variance What is a frequency distribution How is it most often illustrated i It is a summary of data representing frequencies of data in each class ii Most often illustrated using a histogram Median is the most appropriate measure of central tendency when the data is i Positively or negatively skewed ii For categorical use mode for symmetrically distributed use mean for nominal use mean Consider the frequency table on the right on blackboard What is the shape of this distribution i Negatively skewed ii look at the direction of the tail What is the most appropriate measure of tendency for the data in this stem andleaf plot i Median ii because it contains extreme values What is an independent variable A dependent variable i An independent variable is the variable in an experiment controlled by experimenter ii A dependent variable is the variable in an experiment that is responding What is correlation What is represented by the linear correlation coefficient r i Direction and strength True or False The linear correlation coefficient r is a statistic i True because a statistic is a numerical measurement that represents a characteristic of a sample ii there will not be any true or false questions on the test A stock analyst compares the relationship between stock prices and earnings per share to help select a stock for investment What type of study is this i Observational What is meant by the equation O T E i O is the observed score T is the true score E is error What are the four scales of measurement i Nominal ordinal interval ratio y What is reliability i Describes if something is free of error z Name 4 types of reliability i Test retest ii Interrater iii Internal consistency iv Parallel forms aa Each question on the student evaluations at UH consist of a 5 point scale in which 1 means Strongly disagree and 5 means Strongly agree What level of measurement is this i Ordinal bb Which of the following statements is true of data with an ordinal level of measurement i You can calculate a median cc A judge is concerned about the reliability of the field sobriety test used by Houston police She orders two officers to independently apply the test to a group of drivers suspected of intoxication What is she trying to establish i Interrater reliability dd An attorney is concerned that the three components of the field sobriety test do not assess the same thing What is he calling into question i Internal consistency reliability ee In 2002 a group of college students complained that the version of the GRE test that they wrote was more difficult than the previous three versions of the test What are they calling into question i Parallel forms reliability